Some .beta.-lactam compounds which are closely related to the new cephalosporin compounds of this invention are known as disclosed in Japanese Patent Application first publication "Kokai" No. 124790/80, No. 122383/81 and No. 76088/84, and U.K. patent application first publication No. 2128990 A. These known cephalosporin compounds which are disclosed in said Japanese patent application first publications have a .beta.-substituted vinyl group as the side chain at the 3-position of the cephem nucleus, similarly to the cephalosporin compounds according to this invention. However, the new cephalosporin compounds of this invention are different from the above-mentioned known cephalosporin compounds in respect of the kind of the substituent born on the .beta.-position of the .beta.-substituted vinyl group at the 3-position of the cephem nucleus.
Cephalosprin-type antibiotics are known to be highly and broadly active against a variety of gram-positive and gram-negative bacteria. Various kinds of semi-synthesized cephalosporin compounds have already been available commercially and applied clinically for the therapeutic treatment of various infections diseases. But, only a very few ones amongst these semi-synthesized cephalosporin compounds are practically effective against the strains of bacteria of the genus Pseudomonas and Proteus. These known cephalosporin compounds are also degradable by a .beta.-lactamase which is produced by some resistant strains of bacteria, and they exhibit only a poor activity against some resistant strains of bacteria which have now been a target of clinical treatments of bacterial infections (see: W. E. Wick "Cephalosporins and Penicillins, Chemistry and Biology", edited by E. H. Flynn, Academic Press, New York, N.Y., 1972, Chapter 11.)
We, the present inventors, have now succeeded in preparing new cephalosporin compounds represented by the general formula (I) shown below, and have found that said new cephalosporin compounds exhibit activity in a very wide range of the antibacterial spectrum and that these new compounds are highly active not only against a variety of gram-positive and gram-negative bacteria but also against some resistant strains of bacteria.